By Trey Pitsenberger, co-owner
Most often when one thinks of the rhododendron the cool
summer weather of the coast most often comes to mind.
While the largest selection of rhododendrons does occur
in cool summer climates, with careful selection these
beautiful, and useful plants can thrive in the interior
warm summer regions, like our foothills. The key is choosing
the right varieties, the correct placement in the garden,
and then giving them the proper care. Rhododendrons,
especially the large leafed varieties are quite deer
You might be interested in knowing that rhododendrons
include the small leafed plants we know as Azaleas. While
we often separate Azaleas and Rhododendrons into separate
categories, they are both members of the same family,
Rhododendron. While as a general rule most azaleas have
smaller leaves and flowers than Rhododendrons, we cannot
as easily classify Rhododendrons. While many Rhododendrons
have larger leaves and flowers than azaleas, some rhododendrons
look more like azaleas than their larger leafed cousins. ‘Purple
Gem’ rhododendron only grows 2’ high and
3’ wide. It holds azalea like foliage with purplish-blue
blooms. Most people when shown this shrub will think
it is an azalea.
Rhododendrons will tolerate early morning sun, filtered
sun, or complete shade. This makes them great plants
for the east or north side of the property, or as under
story plants below trees. These plants require a rich
acid soil that is both fast draining, yet is moisture
retentive. In the foothills our soil is generally acid
but poor draining. You will want to work in lots of organic
matter before planting. Since rhododendrons are shallow
rooted you must dig the hole three times the width of
the container it comes in. Only dig the hole as deep
as the container as the roots will never go more than
a foot or so into the ground. Mix Master Nursery Planting
mix with the dirt dug from the hole. You want a mix that
is 75% Planting mix to 25% native dirt. Add a Starter
fertilizer high in phosphorus, such as Master Start.
Place the plant in the hole so that the top of the root
ball is about a inch above the surrounding soil. Back
fill with the soil mix. Since the roots grow shallow
a mulch on top of the soil will help keep the roots cool
and moist thru the hot months.
Many people assume that all rhododendrons become quite
large. While some varieties do get as tall as seven feet
plus, there are a large variety that stay compact and
small, some only growing a couple of feet tall and wide. ‘ Cunningham’s
Blush’ has blush pink funnel-shaped flowers in
spring. The plant grows wider than tall, four feet tall
by six feet wide. ‘ Daphnoides’ has foliage
unlike any other Rhododendron. Rolled glossy leaves are
tightly spaced on stems of this dense mounded plant.
Prolific pompon trusses are purple. This plant is very
effective as an accent. ‘Daphnoides’ is a
moderate grower to 4 feet tall and wide. Growing only
to about three feet tall and wider is ‘P.J.M.’ This
variety stands up well to heat, and has bright lavender
pink blooms. ‘Rosamundi’ grows to about four
feet tall and wide and has pretty light pink flowers
with very dark green leaves. The above varieties do well
in the foothills with our hot dry summers and cool winters.
There are many other types suited for our area. The above
are some of my favorites.
When watering rhododendrons, frequent watering is better
than deep watering, infrequently. We are not trying to
get the roots to grow deep. That’s against the
nature of the plant. Use mulch underneath these plants.
Fir mulch or shredded cedar are great for keeping the
roots cool and moist. You want to water frequently enough
that you could keep moss growing underneath. Feed rhododendrons
a couple of times in the spring with an acid food.
Rhododendrons are suited for most areas of the foothills,
from the lower elevations to the higher mountain regions.
If you have a shady area, that could use some good foundation
plants that provide a fantastic flower show in the spring,
rhododendrons just might be the plant for you.